1. Field of the Invention
The present invention relates to a method, and more particularly to a method of manufacturing a light emitting diode with an ultrasonic thermal press technique.
2. Description of Related Art
Conventional method of manufacturing light emitting diodes (LEDs) is to form monocrystalline materials as a light emitting structure on a substrate. Different substrates and light emitting structures result in different colors of the light beam produced by the LED. For example, blue LED is made of indium gallium nitride (InGaN) light emitting structure on a sapphire substrate. Because the sapphire substrate is electronically insulated, positive and negative electrodes must face up and be formed on the blue LED. Accordingly, after manufacturing the wafer on the substrate, steps of forming electrodes, etching the negative electrode area, exposing and cleaning surfaces of the die, detecting characteristics of the emitted light, cutting the die, bonding the die, bonding wires on the die, glue-injecting and the like are still have to be finished subsequently.
Conventional packaging technique usually uses either silver glues or insulating glues to bond the die. However, a common drawback of the silver glue and the insulating glue is that their thermal conductivities are not good. For example, thermal conductivity of the silver glue or the insulating glue is between 0.1 W/mK to 4 W/mK. Therefore, when the LED is used to an application that requires lager power, such as illuminating, the glue having low thermal conductivity results in low illumination and short lifetime. Consequently, a material with high thermal conductivity for bonding the die is required.
To overcome the shortcomings, the present invention provides a method of manufacturing a light emitting diode to mitigate or obviate the aforementioned problems.